By March, the pace of production will rise to full capacity of about 4,000 Leafs a month at the Oppama factory, putting Nissan on track to hit a target of producing a total 10,000 units by the end of March, a Nissan official said.

"We'll build more Leafs in the next two months and add overtime and holidays to keep up with production of the other vehicles on the line," said Seiji Honda, head of the Oppama factory, noting that car demand typically ticks up at the end of Japan's fiscal year in March.

Until production starts at its Tennessee and Sunderland factories in 2012 and 2013, respectively, Nissan will supply the car from Oppama.

Journalists today toured the 430,000-units-a-year Oppama plant, where the Leaf hatchback is assembled on a mixed line alongside gasoline-engine models such as the Juke, Cube, and Note.

With battery packs and electric motors waiting on the side of the trim and assembly lines instead of fuel tanks and engines, the Leaf's frames flowed seamlessly on conveyor belts between those of the Juke crossover and Cube minivan.

The battery modules and other EV-specific parts are put together in a separate "sub-line."

"Right now, about one in every seven cars is a Leaf, and we'll start building more until we reach maximum capacity in March," Honda said.

Nissan has taken orders for 6,000 Leafs in Japan and 20,000 in the United States so far, closing reservations for the time being. It sold the first Leafs in Portugal this month and will begin deliveries in select European markets in the coming months.

Nissan Americas Chief Carlos Tavares said earlier this month the automaker has committed to delivering the Leaf to all 20,000 U.S. customers by September.

Nissan and Renault are preparing factories around the world to manufacture a combined 500,000 lithium-ion batteries a year, mainly for their electric vehicles, by 2015.

The companies' joint CEO, Carlos Ghosn, has predicted that one-tenth of all new vehicles sold worldwide would be all-electric by 2020, and wants the alliance to take the biggest share, much as Toyota Motor has done with gasoline-electric hybrids.